Technical Field
The present invention relates to a system for the production of panels of wooden material, particularly of wood flakes.
Background Art
It is known that to make this type of panel, the raw material, i.e. wood, must be treated in special production facilities where all the phases and treatments occur needed to transform the raw material into panels. The most important macro phases are briefly described below.
In a first macro phase, elongated wood flakes are obtained by shaving treatments.
In a second macro phase, the wood flakes are first dried, usually in special drum or belt dryers, selected and then mixed with resins and glues.
In a third macro phase, the panel is formed.
In particular, the flow of wooden material is conveyed to special forming machines, which also make a kind of selection of the incoming material by separating it into two flake flows substantially homogeneous in size (short flakes and long flakes).
Selection is made by means of swivel distributor elements, sized and arranged in such a way as to drag the long flakes causing them to advance along a direction defined by their direction of rotation and in such a way that the flakes fall in succession onto the conveyor belt arranged below the distributor elements themselves, and arrange themselves in different layers according to their size.
This way the flows of material thus deposited on the conveyor belt are layered one above the other with the flakes oriented according to requirements, so as to form a multilayer mattress of material.
The mattress is then sent to heat presses which heat and compact the material, activating the glues and resins previously applied to the flakes and giving the panel its final thickness.
The known panels, called Oriented Strand Board (OSB), usually consist of at least three layers of wooden material in flakes, of which the outermost layers consist of long flakes and the innermost ones of short flakes.
These panels do have several drawbacks.
This type of panel is mainly used for structural applications and in the shipbuilding sector and is not suitable for applications wherein the aesthetic appearance is of substantial importance.
Moreover, this type of panel is not even suitable for “facing”, i.e., to be treated with waterproofing substances and coated with fine powders, varnishes, paper or other material in order to give the panel a better aesthetic appearance such as to make it suitable for a broader range of applications.
In particular, because the outer layers are made up of the longest flakes, gaps left between one flake and another are larger than gaps present in the intermediate layers.
The presence of such gaps on the outermost layers implies that such panels are not suitable for facing because the surface finish would be inaccurate and of poor quality.
To perform the facing of this type of panels, large quantities of material would have to be applied which would cause an increase both in production costs, because such material has a far from negligible cost, and in the unit weight of the panel, due to the fact that because the material is fine, it will have a considerable weight per unit of volume.
This would entail a considerable increase in the density of the panel, an undesirable feature if this type of panel has to compete, e.g., with the multiply panel which instead has a low density.
Another drawback associated with the extensive use of material used in the outer coating regards the environmental impact which each panel would have, both during the production phase, because fine powders and varnishes are impacting substances, and during transport, because the greater the weight, the greater will be the emissions associated with fuel consumption.